Immersion heater



March 9, 1965 J. J. FINN IMMERSION HEATER Filed July 18, 1965 INVENTOR.

United States Patent "ice 3,172,993 IMMERSION HEATER John J. Finn, Erie, Pa., assignor of one-half to Glenn Electric Heater Corporation, Erie, Pa., a corporation of Pennsylvania Filed July 18, 1963, Ser. No. 295,935 7 Claims. (Cl. 219-336) This invention is intended to improve the installation and operation of immersion heaters.

In the drawing, FIG. 1 is a side elevation of an immersion heater, FIG. 2 is a partial section through the heater installed in a tank, and FIG. 3 is a bottom view, partly broken away.

The invention is shown applied to a three phase heater having three separate sheathed heating elements 1a, 1b, 1c sealed to the inner side of the bottom wall 2 of a cup shaped base and having terminals 3a, 4a, 3b, 4b and 3c, 4c projecting from the outer side of the base.

The heater is installed from the inside of the tank or vessel to be heated. The cylindrical side wall 5 of the base projects through an opening 6 in the wall 7 and a radially projecting flange 8 on the base of larger diameter than the opening seals against a gasket 9. Outside the wall 7 is a clamping ring 10 having a flat surface 11 engaging the outer surface of the wall and in opposed relation to flange S. In the outer part of the cylindrical wall 5 is a circumferential groove 12 slidably receiving tongues 13 of a pressure ring 14. The pressure ring is easily telesooped over the cylindrical side wall 5 of the base when the tongues 13 are in line with axial slots 15 leading to the groove. After assembly, the pressure ring 14 is turned, bringing the tongues out of alignment with the slots. Sealing pressure is then applied by screws 16 threaded into the ring 14 and having ends 16:: hearing on the surface 17 of the ring 19. As the screws are tightened, the ring 10 is pressed against the outer surface of the wall 7, completing the seal. It will be noted that the screws, when tightened, are in compression so that thermal expansion of the screws tends to tighten the seal. There is the further advantage that the ends of the screws are in frictional engagement with the surface 17 so that loosening of the screws under vibration does not occur.

United to the bottom wall 2 is a well 18 having its upper end 18a welded to the uppermost portion of the heating elements. On low liquid level, the rate of heat transfer from the exposed or uppermost portion of the heating elements falls rapidly and it, accordingly, quickly overheats. The temperature of the uppermost portion of the heating elements is transmitted to the well and from the well to an internal conducting rod 19 spaced from the side walls of the well and having a slip connection 20 with a thermostat 22.. The uppermost section of the rod is in good thermal contact with the uppermost section of the well and, accordingly, responsive to the high temperature of the exposed section of the heating elements. The rod has a clearance between it and the inside of the well so that the high temperature of the rod is conducted to the thermostat without appreciable cooling.

The wiring is contained in a box 23 comprising a U- shaped section 24 with its bottom wall 25 fastened to the pressure ring 14 by screws 25a and with side walls 26, on one of which is mounted the thermostat 22. A complementary U-shaped section completes the enclosure of the box. Suitable knockouts for the wiring may be provided in the side walls 26.

What is claimed as new is:

1. In a liquid heater, a tank having a wall with an opening therein, a heater having a cup shaped base with its bottom presented to the interior of the tank and with a cylindrical side wall extending through the opening and having its outer end accessible from the outside of the 3,172,993 Patented Mar. 9, 1965 tank wall, a flange on said base of larger diameter than said opening for sealing against the inside of the tank wall, a sheathed heating element sealed to the bottom of the base and having terminals accessible from the outside of the tank wall, a clamping ring telescoped over said cylindrical wall and having a fiat surface engaging the outside of the tank Wall, said cylindrical wall having a circumferential groove spaced inward from its outer end and axial slots extending from the outer end of the cylindrical wall to the groove, a pressure ring having tangs slidable through said slots into said groove and anchoring the pressure ring in the groove when the pressure ring is turned to bring the tangs out of register with the slots, screws threaded into the pressure ring and having ends engaging and exerting clamping pressure on said clamping ring, and an outlet box having a bottom Wall telescoped over said side wall of the base and secured to said pressure ring.

2. In a liquid heater, a tank having a wall with an opening therein, a heater having a cup shaped base with a bottom presented to the interior of the tank and with a cylindrical side wall extending through the opening and having its outer end accessible from the outside of the tank wall, said base having a sealing surface of larger diameter than said opening for sealing against the inside surface of the tank, a sheathed heating element sealed to the bottom of the base and having terminals within said cylindrical wall and accessible from the outside of the tank wall, a clamping ring telescoped over said cylindrical wall and having a fiat surface engaging the outside of the tank wall, said cylindrical wall having a circumferential groove spaced inward from its outer end, axial slots ex tending from the outer end of the cylindrical wall to the groove, a pressure ring having tanks slidable through said slots into said groove and anchoring the pressure ring in the groove when the pressure ring is turned to bring the tangs out of register with the slots, and screws threaded into the pressure ring and having ends engaging and exerting clamping pressure on said clamping ring.

3. In a liquid heater, a tank having a wall with an opening therein, a heater having a cup shaped base with a bottom presented to the interior of the tank and with a cylindrical side wall extending through the opening and having its outer end accessible from the outside of the tank wall, said base having a sealing surface of larger diameter than said opening for sealing against the inside surface of the tank, a sheathed heating element sealed to the bottom of the base and having terminals within said cylindrical wall and accessible from the outside of the tank Wall, a clamping ring telescoped over said cylindrical wall and having a flat surface engaging the outside of the tank wall, a pressure ring, means for anchoring the pressure ring to the outer end of said cylindrical wall, and screws threaded into the pressure ring and having ends engaging and exerting clamping pressure on said clamping ring.

4. In a liquid heater, a tank having a wall with an opening therein, a heater having a cup shaped base with a bottom presented to the interior of the tank and with a cylindrical side wall extending through the opening and having its outer end accessible from the outside of the tank wall, said base having a sealing surface of larger diameter than said opening for sealing against the inside surface of the tank, a sheathed heating element sealed to the bottom of the base and having terminals within said cylindrical wall and accessible from the outside of the tank Wall, a clamping ring telescoped over said cylindrical wall and having a flat surface engaging the outside of the tank wall, a pressure ring, means for anchoring the pressure ring to the outer end of said cylindrical wall, screws threaded into the pressure ring and having ends engaging and exerting clamping pressure on said clamping ring, and an outlet box having a bottom wall telescoped over said side wall of the base and secured to said pressure ring.

5. In a liquid heater, a tank having a wall with an opening therein, a heater having a cup shaped base with a bottom presented to the interior of the tank and With a cylindrical side wall extending through the opening and having its outer end accessible from the outside of the tank wall, said base having a sealing surface of larger diameter than said opening for sealing against the inside surface of the tank, a sheathed heating element sealed to the bottom of the base and having terminals within said cylindrical wall and accessible from the outside of the tank wall, a clamping ring having a flat surface engaging the outside of the tank Wall, a pressure ring, means for anchoring the pressur ring to the outer end of the cylindrical wall, and screws carried by the pressure ring and in compression between the clamping ring and the pressure ring for exerting clamping pressure on the clamping ring.

6. A heater having a cup shaped base with a bottom and a cylindrical side wall, an outwardly extending flange on said base adjacent the bottom of the base, a sheathed heating element sealed to the bottom of the base and having terminals within said side wall, a clamping ring telescoped over said side wall and having a flat surface in opposed relation to said flange, said side wall having a circumferential groove spaced inward from its outer end, axial slots extending from the outer end of the side wall to the groove, a pressure ring having tangs slidably through said slots into said groove and anchoring the pressure ring in the roove when the ring is turned to bring the tangs out of register with the slots, screws threaded into the pressure ring and having ends engaging and exerting clamping pressure on said clamping ring forcing it toward said flange, and an outlet box having a bottom wall telescoped over said side wail of the base and secured to said pressure ring.

7. A heater having a cup shaped base with a bottom and a cylindrical side wall, an outwardly extending flange on said base adjacent the bottom of the base, a sheathed heating element sealed to the bottom of the base and having terminals within said side wall, a clamping ring telescoped over said side wall and having a flat surface in opposed relation to said flange, a pressure ring anchored to said side wall, and screws carried by the pressure ring and in compression between the pressure ring and the clamping ring for exerting clamping pressure on said clamping ring forcing it toward said flange.

References Cited in the file of this patent UNITED STATES PATENTS 1,870,274 Wulfert et al. Aug. 9, 1932 1,916,804 McNab July 4, 1933 2,286,340 Bulpitt June 16, 1942 2,566,060 Eils et al. Aug. 28, 1951 2,722,595 Kolb Nov. 1, 1955 

1. IN A LIQUID HEATER, A TANK HAVING A WALL WITH AN OPENING THERIN, A HEATER HAVING A CUP SHAPED BASE WITH ITS BOTTOM PRESENTED TO THE INTERIOR OF THE TANK AND WITH A CYLINDRICAL SIDE WALL EXTENDING THROUGH THE OPENING AND HAVING ITS OUTER END ACCESSIBLE FROM THE OUTSIDE OF THE TANK WALL, A FLANGE ON SAID BASE OF LARGER DIAMETER THAN SAID OPENING FOR SEALING AGAINST THE INSIDE OF THE TANK WALL, A SHEATHED HEATING ELEMENT SEALED TO THE BOTTOM OF THE BASE AND HAVING TERMINALS ACCESSIBLE FROM THE OUT SIDE OF THE TANK WALL, A CLAMPING RING TELESCOPED OVER SAID CYLINDRICAL WALL AND HAVING A FLAT SURFACE ENGAGING THE OUTSIDE OF THE TANK WALL, SAID CYLINDRICAL WALL HAVING A CIRCUMFERENTIAL GROOVE SPACED INWARD FROM ITS OUTER END AND AXIAL SLOTS EXTENDING FROM THE OUTER END OF THE CULINDRICAL WALL TO THE GROOVE, A PRESSURE RING HAVING TANGS SLIDABLE THROUGH SAID SLOTS INTO SAID GROOVE AND ANCHORING THE PRESSURE RING IN THE GROOVE WHEN THE PRESSURE RING IS TURNED TO BRING THE TANGS OUT OF REGISTER WITH THE SLOTS, SCREWS THREADED INTO THE PRESSURE RING AND HAVING ENDS ENGAGING AND EXERTING CLAMPING PRESSURE ON SAID CLAMPING RING, AND AN OUTLET BOX HAVING A BOTTOM WALL TELESCOPED OVER SAID SIDE WALL OF THE BASE AND SECURED TO SAID PRESSURE RING. 